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LER-2015-003, Regarding Legacy Wiring Error Impacts Containment Valve Closure Time Surveillances
Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(i); 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability; 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded; 10 CFR 50.73(a)(2)(viii)(A); 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition; 10 CFR 50.73(a)(2)(viii)(B); 10 CFR 50.73(a)(2)(iii); 10 CFR 50.73(a)(2)(ix)(A); 10 CFR 50.73(a)(2)(iv)(A), System Actuation; 10 CFR 50.73(a)(2)(x); 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor; 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat; 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown; 10 CFR 50.73(a)(2)(v), Loss of Safety Function; 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications
	3892015003R00 - NRC Website
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Regarding Legacy Wiring Error Impacts Containment Valve Closure Time Surveillances
	ML16015A008
Person / Time
Site:	Saint Lucie
Issue date:	12/18/2015
From:	Costanzo C; Florida Power & Light Co
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	L-2015-312 LER 15-003-00
	Download: ML16015A008 (4)
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S I PLo December 18, 2015 L-2015-312 10 CFR 50.73 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555 Re:

St. Lucie Unit 2 Docket No. 50-389 Reportable Event: 2015-003 Date of Event: October 19, 2015 Legacy Wiring Error Impacts Containment Valve Closure Time Surveillances The attached Licensee Event Report 2015-003 is being submitted pursuant to the requirements of 10 CFR 50.73 to provide notification of the subject event.

Respectfully, Christopher R. Costanzo Site Vice President St. Lucie Plant CRC/KWF Attachment cc:

NRC Region II Administrator St. Lucie Plant NRC Senior Resident Inspector Florida Power & Light Company 6501 S. Ocean Drive, Jensen Beach, FL 34957

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 01131/2017 (02-2014)

='*'*%Estimated burden per response to comply with thin mandatory collection request: 80 hours9.259259e-4 days 0.0222 hours 1.322751e-4 weeks 3.044e-5 months .

}Reported lessons learned are incorporated into the licensing process and fed back to industry.

Send comments regarding burden estimate to the F0OIA, Privacy and lnformnation Collections LICENSEE EVENT REPORT (LE R)

Branch (T-5 F53), U.S. Nuclear Regulatory Commisnion, Washington, DC 20555-0001, or by

" "intereet e-mail to lnfocollects.Resource@nmc.gov, and to the Desk Officer, Office of information and (See Page 2frrequired number of Regulatory Attairs, NEOE-10202, (3150-0104), Office of Management and Budget, Washington, DC digits/characters for each block) 20503. If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.

13.

PAGE st. Lucie Unit 2 050003891 1

OF 3

4. TITLE Legacy Wiring Error Impacts Containment Valve Closure Time Surveillances

5. EVENT DATE

6. LER NUMBER

7. REPORT DATE I8.

OTHER FACILITIES INVOLVED MONTH DAY YEAR YEAR NUMBER RVNO. MONTH DAY YEAR FAIIT5AM0OC 00NME II~I FACILITY NAME DOCKET NUMBER 10 1

052015 -

003

- 00I12 j

18 2 0 1 5 105000

9. OPERATING MODE

11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)

[]

20.2201(b)

[]

20.2203(a)(3)(J)

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50.73(a)(2)(i)(C)

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50.73(a)(2)(vii)

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20.2201(d)

[]

20.2203(a)(3)(ii)

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50.73(a)(2)(ii)(A)

LII 50.73(a)(2)(viii)(A)

LI 20.2203(a)(1)

[]

20.2203(a)(4)

[]

50.73(a)(2)(ii)(B)

LI 50.73(a)(2)(viii)(B)

L 20.2203(a)(2)(i)

LI 50.36(c)(1 )(i)(A)

LI 50.73(a)(2)(iii)

LI 50.73(a)(2)(ix)(A)

10. POWER LEVEL

[]

20.2203(a)(2)(ii)

[] 50.36(c)(1)(ii)(A)

[] 50.73(a)(2)(iv)(A)

[] 50.73(a)(2)(x)

LI 20.2203(a)(2)(iii)

[] 50.36(c)(2)

LI 50.73(a)(2)(v)(A)

LI 73.71(a)(4)

LI 20.2203(a)(2)(iv)

LI 50.46(a)(3)(ii)

LI 50.73(a)(2)(v)(B)

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73.71 (a)(5)

LI 20.2203(a)(2)(v)

LI 50.73(a)(2)(i)(A)

LI 50.73(a)(2)(v)(C)

LI OTHER LI 20.2203(a)(2)(vi)

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50.73(a)(2)(i)(g)

LI 50.73(a)(2)(v)(D)

Specifin Abstract beloworin

______________NC__FoNRCForm36A

12. LICENSEE CONTACT FOR THIS LER LtCENSEE CONTACT TLPOENME IcueAe oeCUE SYSTEM COMPONENT FACTURER TO EPIX r1 CASFY ANTU-E R

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14. SUPPLEMENTAL REPORT EXPECTED

15. EXPECTED MONTH IDAY IYEAR SUBMISSION Li YES (If yes, complete 15. EXPECTED SUBMISSION DA TE)

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NO DATE e*BSTRACT (Liitto1400 saces, iLe., approximately 15single-spaced tpewritenlies)

On October 19,

2015, during corrective maintenance activities on containment isolation valve FCV-26-3, maintenance personnel discovered that the valve actuator position limit switches were not wired correctly since December 2001.

This condition invalidated previous closure time surveillance results for this valve.

This condition is being reported pursuant to the requirements of 10 CFR. 50.73(a) (2) (i) (B).

The wiring discrepancy was caused by a legacy maintenance human performance issue.

The limit switch wiring was corrected, the post-maintenance testing was completed satisfactorily, and the valve was returned to service.

Description of the Event On October 19,

2015, St. Lucie Unit 2 was in Mode 5 at 0% reactor power.

During corrective maintenance activities on valve FCV-26-3 [ETTS:BD:ISV],

the containment penetration 52B inside isolation valve for the 'B' channel containment air radiation monitor [ETIS:IL],

maintenance personnel discovered that the valve actuator position limit switches [ETIS:33] were not wired correctly.

FPL reviewed the work order history for this valve and determined that the valve actuator limit switches were miss-wired during the SL2-13 December 2001 refueling outage when the environmentally qualified limit switches were replaced.

The limit switch wiring was corrected, the post-maintenance testing was completed satisfactorily, and the valve was returned to service.

Cause of the Event

The limit switch miss-wiring is considered a legacy maintenance human performance event.

FPL is investigating potential weaknesses in the post-maintenance test procedure as a potential contributor to this latent failure.

Analysis of the Event

Valve FCV-26-3 is the inside containment penetration isolation valve for containment penetration 52B which serves the 'B' channel containment atmosphere radiation monitor (FCV-25-4 is its companion outside isolation valve).

Each containment isolation valve actuator contains limit switches for the open and closed position.

As a containment isolation feature, the valve has closure time requirements.

Per procedure, valve closure time is verified by observation of the control room remote valve position indication.

Containment penetrations 52A, 52B, and 52C share isolation valve position indication by ganging the limit switches together for the inside isolation valves (i.e., FCV-26-l, FCV-26-3, and FCV-25-5) and outside isolation valves(i.e.,

FCV-26-2, FCV-26-4, and FCV-25-6).

The limit switch arrangement indicates dual position for the ganged inside and outside isolation valves when each of the three respective flow control valve limit switches are not in the open or closed condition.

The discrepant wiring prevented valve FCV-26-3 from providing its limit switch condition to the common inside containment isolation valve indication scheme for penetrations 52A,

52B, and 52C.

No matter what position FCV-26-3 was actually in, as the ganged valves were stroked it would appear as normal so long as both FCV-26-1 and 5 operated normally.

Because Technical Specification Surveillance Requirement 3/4.6.3.3 verifies valve stroke timing via the remote control room position indication, the containment isolation timing for FCV-26-3 has not been verified since December 2001.

This resulted in operation of the facility in a manner prohibited by the Technical Specifications, as the wiring discrepancy invalidated previous FCV-26-3 closure time surveillance results.

However, every refueling outage FCV-26-3 and its companion valves have their local and remote position indications verified.

Though not a requirement of the procedure, local personnel have observed the valves' open and close strokes as

they are remotely operated from the control room.

Although this does not validate the timing of FCV-26-3, it does provide reasonable assurance that FCV-26-3 stroked in concert and consistent with its companion valves.

In addition to timing requirements, containment isolation valves also have pressure integrity requirements.

Pressure integrity for the containment penetration is tested in accordance with the integrated and local leak rate testing (I/LLRT) requirements, and FPL determined that there have been no containment penetration 52B I/LLRT failures between October 19, 2015 (e.g., the time of discovery) and December 2001 (e.g., when the legacy maintenance occurred).

Based on these test results, FPL concludes that although the actual position indication for FVC-26-3 was inoperative, the penetration integrity was tested satisfactory during the I/LLRT tests, proving the valve was positioning and functioning as a containment isolation feature during the time period between December 2001 and October 2015.

The remaining St. Lucie Unit 2 system 26 isolation valve ganged limit switches will be inspected to ensure that the limit switches are properly wired.

Safety Significance

Although valve closure timing was not tested, the valve did respond to closure signals as demonstrated by successful I/LLRT test results.

Opportunities to observe the valve stroke during local/remote valve position verifications provide reasonable assurance that FCV-26-3 operated with speeds comparable to the other penetration 52A,

52B, and 52C containment isolation valves.

Additionally, FCV 4 passed all surveillances during the subject time period, assuring redundant penetration isolation capability for penetration 52B.

Based on the above, containment integrity was not challenged by this legacy condition.

In addition to post-accident containment isolation matters, had the valve failed closed during normal operation without indication, the 'B' channel containment atmosphere radiation monitor sample pump would trip on low flow, alerting the operators of a potential problem.

Based on the above, the inoperative FCV-26-3 valve position indication and the resultant lack of available closure time test data was not an adverse impact on the health and safety of the public.

Corrective Actions

1. The limit switch wiring for FCV-26-3 was restored to design under work order 40418516.

2.

The remaining Unit 2 containment penetration 52A, 52B, and 52C isolation valves extent of condition will be verified by work order 40433093.

3.

Engineering is reviewing stroke time test methodology for improvement opportunities.

Failed Component(s)

Component: Limit Switch Manufacturer:

NAMCO Model No.: EA180-I1302

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